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about the Axon and the Neuron ...
An axon or nerve fiber is a long, slender projection of a nerve cell,
or neuron, that conducts electrical impulses away from the neuron's cell body or soma.
Anatomy
Axons are in effect the primary transmission lines of the nervous system,
and as bundles they help make up nerves. Individual axons are microscopic in diameter (typically about 1μm across),
but may be up to several feet in length. The longest axons in the human body, for example, are those of the sciatic nerve,
which run from the base of the spine to the big toe of each foot.
These single-cell fibers of the sciatic nerve may extend a meter or even longer.
In vertebrates, the axons of many neurons are sheathed in myelin, which is formed by either of two types of glial cells: Schwann cells ensheathing peripheral neurons and oligodendrocytes insulating those of the central nervous system. Along myelinated nerve fibers, gaps in the sheath known as nodes of Ranvier occur at evenly-spaced intervals, enabling an especially rapid mode of electrical impulse propagation called saltation. The demyelination of axons is what causes the multitude of neurological symptoms found in the disease Multiple Sclerosis. The axons of some neurons branch to form axon collaterals, that can be divided into a number of smaller branches called telodendria. Along these the bifurcated impulse travels simultaneously to signal more than one other cell.
Neurons , also known as neurones and nervous cells are responsive cells in the nervous system that process and transmit information by electrochemical signaling. They are the core components of the brain, the vertebrate spinal cord, the invertebrate ventral nerve cord, and the peripheral nerves. A number of different types of neurons exist: sensory neurons respond to touch, sound, light and numerous other stimuli affecting cells of the sensory organs that then send signals to the spinal cord and brain. Motor neurons receive signals from the brain and spinal cord and cause muscle contractions and affect glands. Inter-neurons connect neurons to other neurons within the brain and spinal cord. Neurons respond to stimuli, and communicate the presence of stimuli to the central nervous system, which processes that information and sends responses to other parts of the body for action.
The information about this subject is edited, and based on this article
editor: H.m.Hanse copyright in accordance with the GNU licence